Tunnel lining



M. MoALPlNE TUNNEL vLINING fled oct. 14,l 1932 Aug. 14, 1934.

lg AM] Patented Aug. 14, 1934 UNITED STATES PATENT OFFICE Application October 14, 1932, Serial No. 637,711 In Great Britain November 19, 1931 1 Claim.

This invention relates to improvements in means for building the curved walls of tunnels, culverts, arches, shafts, wells, aqueducts or the like of concrete or like material.

The object of the invention is to dispose the reinforcing members in the central zone of the segmental elements of the structure in such a way as to enable the whole of the reinforcement to be contained in the segments of the structure and close to the circumferential joints thereof and by placing the reinforcement therein during the manufacture of the segments it will stiffen the segment during the period of setting of the cement and enable the segment to be removed from the mould without risk much earlier than could be done if the reinforcement were absent or had been placed in another position than that defined hereinafter. r

This invention consists of improved means for reinforcing the walls of tunnels, shafts and the like built of concrete or the like comprising the initial casting of tongued and grooved ring segments, each segment having two reinforcing bars centrally disposed therein and substantially parallel with and closely adjacent to the jointing surfaces of each ring of segments. It is advisable to dispose the reinforcing element of one ring relative to that of the next ring in such a manner that the reinforcing element or elements of one ring bridge the longitudinal segmental joints of the adjoining ring and transmit the circumferential stresses from the reinforcing element of one segment to that of the adjacent segment.

In order that the invention may be the better understood I will now proceed to describe the same in relation to the accompanying drawing, reference being had to the letters and gures marked thereon. Like letters refer to like parts in the various figures in which:-

Figure 1 is a cross sectional view of a tunnel or shaft constructed according to this invention,

Figure 2 is a longitudinal section of the same,

Figure 3 is a part sectional view to an enlarged scale showing the reinforcement and Figure 4 is a similar view showing an additional reinforcement of ring formation in a deepened groove in the segmental elements.

In carrying out this invention each segment a is strengthened on each side by a reinforcing bar b disposed in a circumferential direction and extending to nearly the whole of its segmental length and running substantially parallel with and as close as practical to the tongue d or groove e as the case may be. The reinforcing bar b may be of uniform section or may be enlarged or shtailed at its end f or be of the indented form in order to set up a greater resistance than the surface cohesion between the rod and the concrete.

The longitudinal joints g of adjoining segmentally formed rings are preferably staggered as shown in Figure 2 so that a longitudinal joint g in one ring is stiffened by the reinforcing bar b in the adjoining ring in order that the stresses in any one bar are transferred from it to the adjacent bars b in the adjoining rings in a circumferential zig-Zag path.

In some cases, the continuity of stress transmission is improved by the provision of a light reinforcing ring h disposed in the bottom of the deepened interlocking groove e at the side of the segments as shown in Figure 4.

I claim:-

In a tunnel, shaft, or the like tubular structure,

a wall built up of pre-cast concrete rings consisting of longitudinally inter-tongued and grooved segmental elements, the adjacent rings having their longitudinal segmental joints staggered relatively to one another, and each segmental element having a reinforcement bar wholly embedded in the corner of the body thereof parallel with and closely adjacent to the tongued and grooved circumferential joining surfaces.

MALCOLM MCALPINE. 

